Fire Rating Common Wall Garage/Living Room

Status
Not open for further replies.
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician (retired)
Someone asked me this today about fire rated boxes in a single family dwelling. Here are the parameters:

-Attached garage with a common wall for living room
-Living space above and adjacent to garage
-Receptacles in common wall of garage and living room
-Ceiling receptacle in garage ceiling

Are there any requirements for fire rated boxes in the common wall and ceiling?
 
infinity said:
Someone asked me this today about fire rated boxes in a single family dwelling. Here are the parameters:

-Attached garage with a common wall for living room
-Living space above and adjacent to garage
-Receptacles in common wall of garage and living room
-Ceiling receptacle in garage ceiling

Are there any requirements for fire rated boxes in the common wall and ceiling?
Click to expand...



I've seen inspectors not allow recessed cans in the ceiling, or panels in the wall bordering the house, but it seems they have never picked on receptacles, but apparantly they could if they wanted to
 
Yes and no, it's a rated wall, but you don't have to treat it exactly like a rated wall, such as the 24" seperation and what not. You still cannot exceed the 16 sq inches of opening, so no panels or valve boxes for the washer and dryer can be installed in it.
 
infinity said:
Someone asked me this today about fire rated boxes in a single family dwelling. Here are the parameters:

-Attached garage with a common wall for living room
-Living space above and adjacent to garage
-Receptacles in common wall of garage and living room
-Ceiling receptacle in garage ceiling

Are there any requirements for fire rated boxes in the common wall and ceiling?
Click to expand...

Your typical NM boxes have a fire rating if you look in the box.

If you are using recessed cans in the garage ceiling then you would need to box them or they would need to have a rating.

As Cowboyjwc pointed out in single family dwellings the garage separation wall is not a true rated wall, but it must be constructed with a layer of 1/2" sheetrock or equivalent and if there is habitable space above the garage the ceiling must have a layer of 5/8" Type X sheetrock installed on the garage side.

Now a single layer of 1/2" sheetrock has a fire rating of about 15 minutes and 5/8" Type X about 40 Minutes according to the IBC Chapter 7.

Chris
 
Thanks for the info. I remember in a CEU class they mentioned something about panels installed in garage walls but couldn't remember about the boxes. Thanks. :cool:
 
2009 IRC 302.6 states that the dwelling unit must be separated from the garage walls by 1/2" gypsum wall board. It is not a firewall. It doesn't even need to be type X Sheetrock.

"Not less than 1/2-inch gypsum board or equivalent applied to the garage side"


Openings, such as doors, can be 20-min doors but does not need to be. It could be a solid wood door or a steel door.

So back to the question, is a plastic outlet box the equivalence of 1/2" Sheetrock???
 
So back to the question, is a plastic outlet box the equivalence of 1/2" Sheetrock???
Click to expand...

Most if not all plastic NM boxes have a fire rating marked on the box. The ones I use have a 2 hour fire rating which far exceeds the fire rating of a single layer of 1/2" sheetrock which has a finish rating of 15 minutes.

Chris
 
Another thing is to put 2 layers of drywall on the backside of the wall when installing panels on common walls to the garage. It may not truly be required by the IRC (recently adopted here and widely mis-quoted as far as I can see so far), but it keeps people quieted down...
 
Status
Not open for further replies.
Top